1. Field of the Invention
The present invention relates to a non-destructive method for testing the curing level of the cured product of a curable adhesive composition, and to a method for manufacturing an electronic device.
2. Description of the Related Art
In the manufacture of a semiconductor device or other such electronic device in which a bare chip IC or other such electronic parts are mounted on a wiring board, a resin press-bonding connection method featuring the use of a thermosetting paste-form or film-form anisotropic conductive adhesive or insulating adhesive, has been widely utilized because it reduces the number of manufacturing steps and improves productivity.
In this press-bonding connection method, one of the above-mentioned adhesive agents is supplied to the connection site between a wiring board and an electronic part, and heat and pressure are applied to cure the thermosetting adhesive, which ensures good connection reliability. Connection reliability, however, depends on the reactivity of the thermosetting adhesive, and the higher is the reactivity, the higher is the level of curing, and the better is the connection reliability. Ensuring satisfactory connection reliability therefore generally requires that the curing level be raised by increasing the reactivity to between 60 and 90%.
Accordingly, measuring the reactivity of a cured product of thermosetting adhesive after connection (that is, after curing) is essential to ensuring the connection reliability of electronic elements. Such measurement has been performed in the past by FT-IR and DSC methods.
Nevertheless, when an FT-IR or DSC method was used to measure the reactivity of a cured thermosetting adhesive present at the connection site between a wiring board and an electronic part in an electronic device in which said electronic part was mounted to the wiring board, a problem that was encountered was that the electronic device had to be destroyed to collect the cured thermosetting adhesive for testing. Also, this measurement generally took at least several hours, so testing efficiency was poor. This same problem also occurred in measuring the reactivity of the cured product of an active energy-curing type of adhesive that cures when irradiated with UV rays or other such active energy rays.